74 



5- Modlohis [Amygdahan) watsoni Smith. (Plate II, figs. 32, 33). 



1885. Modiola zvatsoni Smith, "Challenger" Laniellibranchia, p. 275, pi. XVI, figs. 5 — ^c. 



1890. Modiola Watsoni Paetel, Cat. Conch. Samm., III, p. igS. 



1891. Modiola sp. Wood-Mason & Alcock, Ann. Mag. Nat. Hist., (6) VII, p. 19. 

 1895. Modiola watsoni Smith, Ann. Mag. Nat. Hist., (6) XVI, p. 14. 



\%i^6. Modiola {Trachidontes) Watsoni Casto de Elera, Cat. Sist. Filip., p. 794. 



1904. Modiola zvatsoni Smith, Ann. Mag. Nat. Hist., (7) XIV, p. 11. 



1905. Modiola Watsoni Hidalgo, Cat. Filip., p. 364. 



1906. Modiola {Amygdaluin) tvatsoni Smith, Ann. Mag. Nat. Hist., (7) XV^III, p. 254. 



191 1. Modiola Watsoni Pelseneer, "Siboga"' Lamellibranches (Anat.), p. 17, pi. IV, figs. 10, ii; 

 pl. V, fig. I. 



I hâve compared the type-shell of this species from west of the Island of Luzon, 

 Philippines (St. 207 "Challenger") with the shells collected by the "Siboga" Expédition and can 

 find no différences between them. The "Sibogfa" shells are somewhat larder and the shell also 

 is consequently a bit thicker. The measurements of the largest shell are: — Length 52 mm., 

 height 28.4 mm., diameter 15.8 mm. 



Distribution: — M. {A.) ivaisoni was originally described from the Philippines, but was 

 later discovered in the Indian (3cean, off the coasts of Ceylon and in the Gulf of Oman. 



The "Siboga" collection contains spécimens from St. 5 (7° 46' S., ii4°3o'.5E.; depth 

 330 mètres). St. 52 (9° 3'. 4 S., ii9°56'.7E. ; depth 959 mètres). St. 88 (o^ 34^.6 N., ii9°8'.5E. ; 

 depth 1301 mètres), St 178 (2°4o'S., i28°37'.5 E.; depth 835 mètres). St. 208 (5°39'S., 

 i22°i2'E.-, depth 1886 mètres), St. 212 (5°54'.5S., i20°i9'.2E.; depth 462 mètres), St. 271 

 (5°46'.7S., i34°o'E.; depth 1788 mètres), St. 284 (8°43'.i S., 127° 16'. 7 E.; depth 828 mètres), 

 St. 300 (io°48'.6S., i23°23'.i E.; depth 918 mètres) and St. 314 (7°36'S., ii7°3o'.8E.; depth 

 694 mètres). 



Modiohis spp. 



In addition to the species enumerated above there are two very young shells from St. 88 

 (0° 34'.6 X., ii9°8'.5E.) and St. 126 (3°27'.i X., i25°i8'.7E.) respectively, which it is not 

 possible to identify specifically. 



Genus Musculus Rôding. 



1798. Musculus Roding, Mus. Boltenianum, p. 156. 



1838. Modiolaria Beck in Robert Comm. Sci. Isl. Groenland, Moll. pl. XVII. 



1846. Modiolaria Lovèn, Ind. Moll. Scand., p. 33. 



1847. Lanistina Gray, Proc. Zool. Soc. London. p. 199. 



1889. Modiolaria Clessin in Martini, Chemn. Conch. -Cab., (N. F.), VIII (3), Mitiliacea, p. 140. 



1898. Modiolaria Dali, Trans. Wagner Free Inst. Sci, Philadelphia, III, p. 804. 



1905. Modiolaria Jukes-Browne, Proc. Malacol. Soc. London, VI, p. 223. 



191 3. Modiolaria Suter, Man. New Zealand Moll., p. 868. 



1915. Musculus Dali, Nautilus, XXVIII, p. 138. 



191 5. Mîisculus Iredale, Journ. Conch., XIV, p. 342. 



For a detailed account of the controversy in référence to the earlier name Modiolaria 

 référence may be made to Dall's work (1898), cited above. In vievv, however, of Iredale having 



